This application is based on and claims priority to Japanese Patent Application No. 10-339,860, filed Nov. 30, 1998.
The present invention generally relates to engine compartment ventilation systems for personal watercraft. More particularly, the present invention relates ventilation systems having air outlets strategically positioned within engine compartments of personal watercraft.
As is well known, engines powered by internal combustion engines that are mounted inboard of the hull and within an engine compartment require adequate ventilation of the engine compartment. It is desirable to ensure that adequate air can reach the engine for combustion and also to purge the engine compartment from unwanted vapors. This problem, although easily handled with larger watercraft, presents a number of problems in conjunction with a smaller type of watercraft known as a xe2x80x9cpersonal watercraft.xe2x80x9d
Personal watercraft are a relatively small type of watercraft wherein the rider sits more upon than in the watercraft. This type of watercraft is designed to be operated primarily by a single rider, although accommodations are frequently made for one or more passengers in addition to the operators. With this type of watercraft, the engine compartment is frequently formed below the rider""s area or immediately forwardly of it.
This type of watercraft is quite sporting in nature and thus the rider and passengers frequently wear swimming suits when riding this type of watercraft. Thus, they expect to receive a fairly large amount of water spray during the watercraft operation. Because of this, there is a fair amount of water spray around the environment of the watercraft and this can easily enter the engine compartment through the ventilating system. Additionally, the watercraft can be easily overturned and at least partially submerged (and the occupants and users recognize that this is a distinct possibility) which further increases the risk of water intrusion. Of course, it is desirable to protect the engine and its auxiliaries from this water. Various arrangements have been proposed, therefore, for providing ventilation of the engine compartment while, at the same time, precluding water ingestion.
With the small type of watercraft involved, it is important to ensure adequate ventilating airflow but also to ensure that water will not enter the engine compartment through the ventilating system. Moreover, engine compartment temperature is also a prominent concern. For the reasons aforenoted, properly structuring a ventilation system that addresses each of these considerations is particularly difficult with personal-type watercraft.
It is, therefore, an object of the present invention to provide an improved engine compartment ventilating system for a personal watercraft. It is a further object of the present invention to provide a ventilating arrangement for a personal watercraft that will provide adequate ventilation and also will provide good assurance that water will not be inadvertently drawn into the engine compartment along with the ventilating air. Moreover, because engines operating in enclosed environments are prone to overheating without adequate air circulation about them, another object of the present invention is to direct cooling air flow to specific high temperature components to increase heat transfer away from the same components.
With this type of watercraft, the hull is generally made up of two major components, a lower hull under portion and an upper deck portion. The engine compartment is normally formed between these two hull portions and the two portions are generally sealed together to form an enclosed chamber. Because of this type of construction, it is relatively difficult to provide a good ventilating system that will achieve the aforenoted effects.
Accordingly, one aspect of the present invention involves a personal watercraft having a hull defining an engine compartment. An internal combustion engine is positioned in the engine compartment and a seat is positioned above at least a portion of the engine. A pedestal supports the seat. The watercraft includes a water propulsion device and the engine has an output shaft arranged to power the water propulsion device. At least one pedestal air duct, which is disposed on a sidewall of the pedestal, is in communication with the engine compartment. The duct has a first end extending through the pedestal, and a second end positioned within the engine compartment.
Another aspect of the present invention involves a personal watercraft comprising a hull defining an engine compartment. An internal combustion engine is mounted within the engine compartment and has a crankshaft. A lubrication system is associated with the engine and includes a lubricant reservoir that is in fluid communication with at least a portion of the engine. A seat is removably attached to the hull and is positioned above at least a portion of the engine. A ventilation duct extends between an exterior of the watercraft and the engine compartment. The ventilation duct has an end disposed within the engine compartment proximate a portion of the engine to which the lubricant reservoir is attached. The end of the ventilation duct is oriented in the engine compartment to direct a flow of ventilating air toward the portion of the engine supporting the lubricant reservoir.